Reactive pyridine-based monoazo colorants having the formulae (1) and (2) as shown below have been known to be colorants having excellent light fastness and wet colored fastness which permit dyeing of mixed fibers of cellulose and polyester. ##STR4##
The monoazo colorants of formulae (1) and (2) are disclosed in Japanese Patent Application (OPI) Nos. 15558/83, and 47060/83, respectively.
The term "OPI" as used herein means a "published unexamined patent application".
The colorants having the formula (1), however, have a problem in that the rubbing fastness after dyeing is poor because in dyeing mixed fibers of cellulose and polyester in dense color, the dyeing ability is insufficiently low and thus colorants not completely dyed remain on the fiber surface.
On the other hand, the colorants having the formula (2) have a problem in that in dyeing of mixed fibers of cellulose and polyester in dense color, the solvent fastness e.g., resistance against dry cleaning is poor although the rubbing fastness is relatively acceptable.